Unintentional Recovery of Parasitic Diversity Following Restoration of Red Deer (Cervus elaphus) in North-Western Italy

Abstract

Red deer (Cervus elaphus) populations in north-western Italy have been remodeled in recent decades. Multiple translocations and the spontaneous migration from Switzerland and France resulted in the successful redistribution of the red deer after human-driven extirpation during the 18th century. The scarcely diverse parasitic community harbored by these cervids has been enriched with two species-specific taxa, Onchocerca jakutensis and Phayigomyia picta, suggesting that the recovery of parasitic biodiversity could be included amongst future conservation goals of this intensively managed game. Nodular onchocercosis was reported in three red deer populations since 2011, while nasal bots were reported since 2018. Hypoderma spp. larvae were identified for the first time in 1989, then a second record was made in 2014 in the province of Biella, where a yearling male in poor condition infested with Hypoderma diana was observed. In the perspective that the restoration of species-specific parasite communities of native mammals in Europe is increasingly perceived as a conservation target, with similar dignity as the conservation of their hosts, baseline data presented in this communication may give new insights for future parasite conservation efforts.

Keywords: nasal bot; nodular onchocercosis; parasitic biodiversity; red deer; translocations; warble fly; wildlife.

Figure 1

Map of NW Italy showing the hunting management units where RD were translocated between 1962 and 2005. The red circles highlight the areas under passive surveillance for macroscopic external parasites (RD1 = Ossola Valleys; RD2 = Gran S. Bernardo and Valpelline Valleys; RD3 = Susa and Chisone-Germanasca Valleys). Arrows indicate the zones that were initially recolonized by RD migrated from Switzerland (CH) and France (FR). The yellow dot corresponds to the Natural Park of La Mandria. Names of the country in the colored areas represent the origin country of the RD population. Borders of provinces adapted from: Regione Piemonte—A1613B—Sistema informativo territoriale e ambientale (https://www.geoportale.piemonte.it/geonetwork/srv/eng/catalog.search#/metadata/r_piemon:94c85f56-4755-470a-8587-f4644b19ccbd, accessed on 10 March 2022). Borders of hunting management units adapted from: Regione Piemonte—A1709C—Infrastrutture, territorio rurale, calamità naturali in agricoltura, caccia e pesca (https://www.geoportale.piemonte.it/geonetwork/srv/eng/catalog.search#/metadata/r_piemon:d4e3df50-bc23-4be5-8825-b9b2c4b218fc, accessed on 10 March 2022). Hill shades adapted from: OpenMapTiles.org © MapTiler © OpenStreetMap contributors.

Figure 2

Macroscopic view on Hypoderma diana (A), Onchocerca jakutensis nodules (B), Pharyngomya picta (C) on deer from different areas of Piedmont (see Figure 3).

Figure 3

Location (by municipality) of the cases of nodular onchocercosis reported in the surveyed RD populations since the first detection in 2011 (a), and cases of nasal bot infestation in the surveyed RD populations since the first detection in 2018 (b). Borders of provinces adapted from: Regione Piemonte—A1613B—Sistema informativo territoriale e ambientale (https://www.geoportale.piemonte.it/geonetwork/srv/eng/catalog.search#/metadata/r_piemon:94c85f56-4755-470a-8587-f4644b19ccbd, accessed on 10 March 2022). Hill shades adapted from: OpenMapTiles.org © MapTiler © OpenStreetMap contributors.